Thermoplastic polymers having a high degree of heat resistance or thermal stability are the object of intensive research and development in many laboratories throughout the world. Since thermoplastic materials comprising these polymers can be molded rapidly and efficiently to articles of simple or complex design, mass production techniques can be utilized to provide a wide variety of useful products. Heat resistant thermoplastic polymers thus offer important advantages that can be used in applications such as electrical components, wire coatings, automotive parts, aircraft parts and the like. Often such polymers can be used in the form of composite materials which contain high temperature resistant fibers and fillers.
However, to be fully exploited for such applications the thermoplastic polymer should have good melt stability characteristics i.e. be able to withstand for a period of time the high temperatures encountered in molding operations without excessive degradation and/or premature curing.
Arylene sulfide/sulfone polymers are thermoplastic polymers known in the art, and processes for making these polymers are disclosed in various U.S. patents of R. W. Campbell, e.g. 4,016,145, 4,127,713 and 4,301,274. Although these patents represent significant and valuable advances in the art, there is a need for a simplified process which can provide aromatic sulfide/sulfone polymers having good melt flow stability as well as high molecular weight.
Accordingly, an object of our invention is to produce aromatic sulfide/sulfone polymers exhibiting high molecular weight.
Another object of our invention is to provide a process for producing high molecular weight aromatic sulfice/sulfone polymers exhibiting improved melt flow stability.
It is a further object of our invention to provide a simplified, readily controllable process for producing high molecular weight aromatic sulfide/sulfone polymers exhibiting improved melt flow stability.
Other objects and aspects, as well as the several advantages of our invention are apparent from a study of this disclosure and the appended claims.